Laser Source Driving Circuit for Speckle-Reduced Projection
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Solution Overview
Problem
Laser projection systems face the issue of speckle phenomenon due to high coherence of laser beams, which affects the projection effect by causing bright and dark dots on the image.
Innovation Solution
A laser projection apparatus is designed with a laser source assembly, optical engine, and projection lens, where the signal shaping circuit increases the frequency of the driving signal to modulate the laser source assembly, reducing coherence by frequently turning the lasers on and off, thereby reducing speckle patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser beams with high coherence are used for projection, then the brightness and intensity of the projected image are improved, but the speckle phenomenon occurs causing bright and dark dots on the image
Solution Approach 1:
The patent applies periodic action by modulating the laser source assembly with a driving signal that has a frequency higher than the image signal frequency. This causes the laser to be frequently turned on and off in a periodic manner, which reduces the coherence of the laser beams while maintaining the brightness of the projected image, thereby eliminating the speckle phenomenon
Solution Approach 2:
The patent changes the temporal characteristics parameter of the laser output by increasing the frequency of the driving signal. This parameter change reduces the coherence time of the laser beams, which suppresses the speckle phenomenon while preserving the illumination intensity needed for bright projection
2Object-affected harmful factors
If the frequency of the driving signal is increased to reduce coherence, then the speckle phenomenon is reduced, but the complexity of the driving circuit increases
Solution Approach 1:
The patent merges the signal shaping function into the existing driving circuit architecture. The driving circuit is designed to integrate both the image signal processing and the high-frequency modulation functions, reducing the need for separate additional circuitry and minimizing overall system complexity while achieving speckle reduction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the coherence of laser beams, minimizing the speckle phenomenon and enhancing the projection image quality.
Implementation Method 1
A laser projection apparatus is designed with a laser source assembly, optical engine, and projection lens, where the signal shaping circuit increases the frequency of the driving signal to modulate the laser source assembly
Data Source
AI summary
A laser projection apparatus includes a laser source assembly, a display control circuit, a signal shaping circuit and a laser source driving circuit. The display control circuit is configured to output a first driving signal and a second driving signal. The signal shaping circuit is coupled to the laser source driving circuit, and is configured to shape the first driving signal based on a shaping signal to obtain a target driving signal. A frequency of the target driving signal is higher than a frequency of the first driving signal. The laser source driving circuit is coupled to the laser source assembly, and is configured to receive the second driving signal and the target driving signal, and drive the laser source assembly to be turned on or turned off in response to the second driving signal and the target driving signal.